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E60 / E61 (2004 - 2010) BMW 5-Series E60 Sedan was first seen in the Unites States in the fall of 2003 with a 2004 Model Year designation. The E61 wagon followed shortly there after. The E60/E61 5 series is now available as a 528i, 528xi, 535i, 535xi, 550i and a 535xi sports wagon! -- View the E60 Wiki

Hi. Just bought an E61 2004 but sounds like the bearings are shot on the alternator. The car has only done 57000 miles. Is it possible to replace the bearings or do I need to bin it and buy a new one? thanks for your help.

Hi. Just bought an E61 2004 but sounds like the bearings are shot on the alternator. The car has only done 57000 miles. Is it possible to replace the bearings or do I need to bin it and buy a new one? thanks for your help.

If you feel the alternator is shot, its best to replace it. Don't know if you save some money (core) over there in the UK for turning in the bad one, but it's best to get a new one.

Hi. Just bought an E61 2004 but sounds like the bearings are shot on the alternator. The car has only done 57000 miles. Is it possible to replace the bearings or do I need to bin it and buy a new one? thanks for your help.

Most cases, even at dealer, people get a rebuilt one; not brand new, it's just too expensive.
Are you sure it's the bearing not belt-tensioner?

Is changing the bearings on the alternator something that can be done at home? i.e. any special tools needed apart from a punch and hammer

It's not that involved to replace bearings on in the alternator. Do you have a place near you that sells [correct] bearings for your alternator? After you open the alternator, you may realize the brushes also may need to be changed.

I recently changed the alternator on my 545i, and given the number of other components that need to be removed in order to pull out the old alternator and fit in the new, I decided to go with a brand new unit.

My problem was wildly swinging voltage output, a function of the voltage regulator, which can be replaced separately from the main unit.

The alternator is basically a large electric motor which is wired to produce electrical current when the serpentine belt spins wound coils that are attached to the pulley shaft within an a magnetic field, rather than accept electrical current and produce work. The internal coils are wound using magnet wire, which is bare wire that is coated (insulated) with varnish so that it can be wound tightly with little gap between wires. You can look in the front of most alternators and see this wound wire. It looks like bare wire, but it is not. This varnish can eventually break down due to heat and over voltage. When it does it can short to a wire next to it, removing some of the turns from the coil and changing the coil's electrical characteristics. Typically there is high resistance to the current at the short leading to high heat in the coil. In order to correctly test that these coils are fully intact and that the electrical insulation has not broken down, the coils need to have a high-potential test run, which subjects the coil to several thousand volts to see if the current bleeds to other components in the assembly. Coils can also be subjected to inductance tests.

Brushes, voltage regulators and other components can also be tested or examined and replaced.

In my case, while I knew how to fully test the alternator electrically, I did not have the proper hi-pot equipment and have heard bad stories about the variations in quality of rebuilt alternators, where sometimes short cuts are taken. A rebuilt alternator is typically not rebuilt from the ground up. Coils are not always removed and tested. Bearings are not always replaced. Sure, almost everyone gives a great warranty (some lifetime), but if the alternator goes bad it still has to be pulled from the vehicle to be returned.

As far as I knew the alternator in my 545i was original, meaning it was eight years old, with 85K miles on it. The entire alternator, not just the one failed component, had been stressed with heat and duty the whole time. I was not willing to risk either just replacing the regulator, or purchasing an unknown rebuilt unit (that might have 125K miles on it before being rebuilt) given the amount of work that needed to be done to replace it if it failed shortly after installation.

I purchased a brand new Valeo unit for $283 delivered. Given the critical nature of the electrical supply in the computer laden BMWs I felt a new unit was peace of mind and worth every penny.

Where did you buy brand new alternator for $283 incl shipping?
Lowest price I found for 180 Amp VALEO alternator for my '06 530i is around $475.

I admit I am ferret-like when searching for part prices on the web. I usually start by searching the BMW PN. But as I receive equivalent manufacturer's PNs I start searching them as well until I develop a picture of pricing.

THESE PRICES ARE FOR BRAND NEW UNITS WITH SHIPPING INCLUDED.

Here is the source I purchased from: "car parts warehouse dot com" (all one word - for some reason this forum doesn't like this website and blocked all attempts to insert an actual link to the URL or even spell out the home page.

The brand new Valeo alternator for my 545i was $283 delivered. Although it is shown at $301, I had a reference elsewhere on the web from the same company at $283 on sale, so when I ordered by phone they said sure, if you have seen an ad for $283 we will match that (I also wanted to confirm it was brand new and came with the pulley attached). Phone sales person then rushed me off the phone saying their warehouse was closing in 15 minutes and he wanted to get the order to the warehouse so it could ship that day. It did ship that day. Great service!

Their price for a new Bosch unit for a 155 Amp Bosch unit of a 530i is $269.

I agree with bimmerfan52's logic in going with new alternator given that it's not super expensive. Even if the remanufactured/rebuilt one comes with warranty, you will have to remove it and take it back. On N52 engine, it's not bad; however, it looks like it's a lot of work on a 545. If you are DIY guy and understand the both pro/cons of having the alternator rebuilt, then go ahead and have the bearings [and brushes, if necessary] replaced. Otherwise, buy a new one and have peace of mind.